Mary,
I think you are right. The John Grisham from Cherokee Co., Texas is the son of Thomas Gresham b. in Wshington Co., Tenn and Rhoda Crouch Gresham.
John Grisham m. Arabelle Reynolds 12 16 1856, Marriage Book C,. p# 24, Cherokee Co., Tx.
Their ancestors came From Maryland to Virginia and on to Tenn and Texas.